Epidermal growth factor receptor pathway substrate 8 (Eps8) is one of crucial kinase substrates for the epidermal growth factor receptors. Eps8 is related to mitosis and differentiation of normal cells. In recent years, it has been demonstrated that Eps8 involves in proliferation, metastasis and prognosis of many malignant tumors. Experiments have shown that Eps8 involves in Ras-Rac pathway of EGFR signaling by forming Eps8-Abi1-Sos1 tri-complex or participates in endocytosis mediated by rab5. Furthermore, Eps8 has also been found to regulate cell cycle. In conclusion, it may become a monitor and a new target for the treatment of malignant tumors. This review briefly introduces molecular structure and physiological function of Eps8, focusing on its function and molecular mechanism in proliferation, metastasis and prognosis of malignant tumors.